.black_overlay{ 
            display: none; 
            position: absolute; 
            top: 0%; 
            left: 0%; 
            width: 100%; 
            height: 100%; 
            background-color: black; 
            z-index:1001; 
            -moz-opacity: 0.8; 
            opacity:.80; 
            filter: alpha(opacity=88); 
        } 
.white_content { 
            display: none; 
            position: absolute; 
            top: 10%; 
            left: 25%; 
            width: 50%; 
            height: 40%; 
            border: 10px solid blue; 
            background-color: white; 
            z-index:1002; 
            overflow: auto; 
        } 